Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.electronics.repair
|
|||
|
|||
Sony DAV-SA30 Power Supply
Hello Guys,
I have a Sony DAV-SA30 DVD surround system. It has been making a ticking noise through the speakers so I thought I'd have a look inside.. I found that the power supply module, 1-687-086-15, is supplying 34.7volts on it's 27v output. The 27v supply is high wattage to the amplifier card, it goes at follows: + from rectifier goes to the pin 1 of Q904, a 3 pin chip. Pin 2 of Q904 goes to the connector that supplies +27v to the amp. Pin 3 has a thin PCB trace going to various surface mount components presumably to control the voltage level. I am trying to locate the fault but cannot identify Q904, it is labeled PK K1189 33. What do you think is my best bet for repair? Maybe a new voltage regulator bypassing this Q904? Any ideas gratefully received! Kris. |
#2
Posted to sci.electronics.repair
|
|||
|
|||
Sony DAV-SA30 Power Supply
On Wed, 26 Apr 2006 21:01:22 +0200, real_pixie
put finger to keyboard and composed: Hello Guys, I have a Sony DAV-SA30 DVD surround system. It has been making a ticking noise through the speakers so I thought I'd have a look inside.. I found that the power supply module, 1-687-086-15, is supplying 34.7volts on it's 27v output. The 27v supply is high wattage to the amplifier card, it goes at follows: + from rectifier goes to the pin 1 of Q904, a 3 pin chip. Pin 2 of Q904 goes to the connector that supplies +27v to the amp. Pin 3 has a thin PCB trace going to various surface mount components presumably to control the voltage level. I am trying to locate the fault but cannot identify Q904, it is labeled PK K1189 33. 2SK1189 MOSFET? http://www.sanken-ele.co.jp/en/prod/...f/2sk1189e.pdf What do you think is my best bet for repair? Maybe a new voltage regulator bypassing this Q904? Check the drive to the gate of the MOSFET. Check for a D-S short circuit. Any ideas gratefully received! Kris. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
#3
Posted to sci.electronics.repair
|
|||
|
|||
Sony DAV-SA30 Power Supply
Franc Zabkar wrote:
On Wed, 26 Apr 2006 21:01:22 +0200, real_pixie put finger to keyboard and composed: Hello Guys, I have a Sony DAV-SA30 DVD surround system. It has been making a ticking noise through the speakers so I thought I'd have a look inside.. I found that the power supply module, 1-687-086-15, is supplying 34.7volts on it's 27v output. The 27v supply is high wattage to the amplifier card, it goes at follows: + from rectifier goes to the pin 1 of Q904, a 3 pin chip. Pin 2 of Q904 goes to the connector that supplies +27v to the amp. Pin 3 has a thin PCB trace going to various surface mount components presumably to control the voltage level. I am trying to locate the fault but cannot identify Q904, it is labeled PK K1189 33. 2SK1189 MOSFET? http://www.sanken-ele.co.jp/en/prod/...f/2sk1189e.pdf What do you think is my best bet for repair? Maybe a new voltage regulator bypassing this Q904? Check the drive to the gate of the MOSFET. Check for a D-S short circuit. Any ideas gratefully received! Kris. - Franc Zabkar Thanks Franc, I have removed the MOSFET from the board and tested the resistance between pins, D-S is approx 1 ohm, which I understand would be correct for a MOSFET, the gate pin has only 10 ohm resistance to both the D and S. I think this may be the problem, I believe MOSFET G-D/S resistance should be very high. I'll get hold of a new MOSFET and give it a try. Do you think the 34v going back through the gate will have damaged the drive circuitry? Thanks for your help so far, Kris. |
#4
Posted to sci.electronics.repair
|
|||
|
|||
Sony DAV-SA30 Power Supply
On Thu, 27 Apr 2006 19:24:43 +0200, real_pixie put finger to keyboard and composed: Franc Zabkar wrote: On Wed, 26 Apr 2006 21:01:22 +0200, real_pixie put finger to keyboard and composed: Hello Guys, I have a Sony DAV-SA30 DVD surround system. It has been making a ticking noise through the speakers so I thought I'd have a look inside.. I found that the power supply module, 1-687-086-15, is supplying 34.7volts on it's 27v output. The 27v supply is high wattage to the amplifier card, it goes at follows: + from rectifier goes to the pin 1 of Q904, a 3 pin chip. Pin 2 of Q904 goes to the connector that supplies +27v to the amp. Pin 3 has a thin PCB trace going to various surface mount components presumably to control the voltage level. I am trying to locate the fault but cannot identify Q904, it is labeled PK K1189 33. 2SK1189 MOSFET? http://www.sanken-ele.co.jp/en/prod/...f/2sk1189e.pdf What do you think is my best bet for repair? Maybe a new voltage regulator bypassing this Q904? Check the drive to the gate of the MOSFET. Check for a D-S short circuit. Any ideas gratefully received! Kris. - Franc Zabkar Thanks Franc, I have removed the MOSFET from the board and tested the resistance between pins, D-S is approx 1 ohm, which I understand would be correct for a MOSFET, the gate pin has only 10 ohm resistance to both the D and S. I think this may be the problem, I believe MOSFET G-D/S resistance should be very high. I'll get hold of a new MOSFET and give it a try. Do you think the 34v going back through the gate will have damaged the drive circuitry? Thanks for your help so far, Kris. There should not be a D-S short in your MOSFET. Replace it and verify that any other device attached to its gate has not been damaged. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
OT Guns more Guns | Metalworking | |||
Sony CFS-W600 Dual Tape Portable Stereo - power supply xfrm failure | Electronics Repair | |||
TV Sony KV27TS35 switching power supply problems | Electronics Repair | |||
Epson ELP 7200 Projector Power Supply Help | Electronics Repair | |||
SONY DVP-NS300 POWER SUPPLY | Electronics Repair |